This application is based on Application No. 2001-24010, filed in Japan on Jan. 31, 2001, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a driving force storing device for a switch operating mechanism, which is employed in the switch operating mechanism for opening and closing, for example, a power switch installed at a substation or a switching station, and stores a driving force from torsion bar elasticity for opening/closing operations.
2. Description of the Related Art
FIG. 11 is a perspective view showing a conventional driving force storing device for a switch operating mechanism, and FIG. 12 is a perspective view showing the joint device in FIG. 11.
In the figures, a driving force storing device which stores a rotational driving force for driving a switch is provided with a first torsion bar 1, a second torsion bar 2, and a joint device 40 joining the first torsion bar 1 and the second torsion bar 2.
The joint device 40 has a first joint portion 3 to which one end of the first torsion bar 1 is fixed, and a second joint portion 4 to which one end of the second torsion bar 2 is fixed.
The other end of the second torsion bar 2 is fixed to a fixed member 9 fixed to a fixed part (not shown), that is, for example, a housing or the like, of this switch operating mechanism. The first joint portion 3 and the second joint portion 4 are rotatably coupled to one another by a pin 5. The pin 5 is inserted into a hole 40a penetrating a concave-convex portion 3a of the first joint portion 3 and a concave-convex portion 4a of the second joint portion 4. A spacer body 6 is inserted between the first joint portion 3 and the second joint portion 4.
Further, the first and second joint portions 3 and 4 are tightened by a bolt 7 and a nut 8. Initial torque of the driving force storing device is adjusted by changing the distance between the first torsion bar 1 and the second torsion bar 2 by changing the thickness of the spacer body 6. Furthermore, the thickness of the spacer body 6 is adjusted by changing the number or the thickness of spacers constituting the spacer body 6.
The other end of the first torsion bar 1 is fixed to a driving shaft portion 10. The driving shaft portion 10 is supported by bearings 11 and 12 fixed to the housing of the switch operating mechanism. A first lever 13 is fixed to the driving shaft portion 10, and the first lever 13 is mechanically connected to a second lever 17 through a link bar 14 to interlock with the second lever 17.
The second lever 17 is fixed to a rotation shaft 18 of a larger gear 22. The rotation shaft 18 is supported by bearings 19 and 20 fixed to the housing of the switch operating mechanism. A one way clutch (backstop clutch) 21 is provided between the rotation shaft 18 and the larger gear 22. When the larger gear 22 is rotated in the direction of arrow I, the rotation shaft 18 is rotated in the same direction. However, when the larger gear 22 is rotated in the reverse direction of arrow I, the rotation is not transmitted to the larger gear 22.
The larger gear 22 is meshed with a smaller gear 23. The smaller gear 23 is rotated by a motor 24.
Next, the operation will be described. When the motor 24 is driven and the smaller gear 23 is rotated in the direction of arrow G at the given number of revolutions, the larger gear 22 is rotated only to a given angle in the direction of arrow I. The rotational motion in the direction of arrow I of the larger gear 22 is transmitted to the second lever 17 through the one way clutch 21 and the rotation shaft 18, thereby moving the link bar 14 in the direction of arrow H.
When the link bar 14 is moved in the direction of arrow H, the first lever 13 is pivoted in the direction of arrow K and first torsion bar 1 is twisted in the given angle about its center axis. When the first torsion bar 1 as a rod-like elastic body is twisted and the second torsion bar 2 as a rod-like elastic body connected to the first torsion bar 1 through the joint device 40 is twisted, resilient forces are stored in the first and second torsion bars 1 and 2.
Thus, when the first lever 13 is pivoted to the given angle and the driving force storing device becomes a fully stored state where the driving force storing device keeps the given resilient forces, the driving power supply of the motor 24 is cut by a limit switch (not shown) and the motor 24 is stopped. At this time, the first lever 13 is held at the position of the aforementioned fully stored state by a latch mechanism (not shown) provided in the switch operating mechanism. Accordingly, the resilient forces of the first and second torsion bars 1 and 2 are maintained stored as they are.
The resilient forces stored in the driving force storing device are released instantly by unlatching the above latch mechanism. After releasing the resilient forces, the first and second torsion bars 1 and 2 return to a state where only the initial torque is stored. When the resilient forces of the driving force storing device are released, the driving shaft portion 10 connected to the first torsion bar 1 is rotated, and an opening/closing operating portion of the switch, which is connected to the driving shaft portion 10 is driven to be opened or closed.
In such a conventional driving force storing device for the switch operating mechanism as described above, since the direction of the torque applied to the joint device 40 by the first and second torsion bars 1 and 2 is the direction for clamping the spacer body 6, an excessive bending force is applied to the pin 5 located on the opposite side. For reducing the bending load applied to the pin 5, the first and second joint portions 3 and 4 are provided with the concave-convex portions 3a and 4a, respectively. Accordingly, complicated machining is required at the time of fabricating the first and second joint portions 3 and 4, increasing the production cost, so the whole apparatus becomes costly.
In order to solve the above-noted defects, an object of the present invention is to provide a driving force storing device for a switch operating mechanism which can reduce production costs by simplifying the construction of parts, to reduce the price of the whole apparatus.
To this end, according to one aspect of the present invention, there is provided a driving force storing device for a switch operating mechanism, comprising: a joint device having a first joint portion on which a first opposing surface is formed, a second joint portion on which a second opposing surface opposing the first opposing surface is formed, and a coupling portion coupling the first joint portion with the second joint portion so that a distance between the first and second opposing surfaces is changeable; a driving shaft portion mechanically connected to an operating portion of the switch operating mechanism, the driving shaft portion being rotatable between a stored position and a released position; a first torsion bar connected between the first joint portion and the driving shaft portion, for storing a driving force by increasing the degree of twisting by rotating the driving shaft portion from the released position to the stored position, and for rotating the driving shaft portion from the stored position to the released position at the time of releasing; a fixed member fixed to a fixed part of the switch operating mechanism; a second torsion bar connected between the second joint portion and the fixed member; and an initial torque adjusting mechanism for adjusting an initial torque applied to the driving shaft portion positioned at the released position by adjusting a distance between the first and second opposing surfaces; wherein a torque is applied to the joint device by the first and second torsion bars in a direction where the first and second opposing surfaces are separated from each other and the first and second joint portions are pushed toward the coupling portion.
According to another aspect of the present invention, there is provided a driving force storing device for a switch operating mechanism, comprising: a joint member; a driving shaft portion mechanically connected to an operating portion of the switch operating mechanism, the driving shaft portion being rotatable between a stored position and a released position; a first torsion bar connected between the joint member and the driving shaft portion, for storing a driving force by increasing the degree of twisting by rotating the driving shaft portion from the released position to the stored position, and for rotating the driving shaft portion from the stored position to the released position at the time of releasing; a fixed member fixed to a fixed part of the switch operating mechanism; and a second torsion bar connected between the joint member and the fixed member; wherein a fixing angle of the fixed member against the fixed part of the switch operating mechanism is adjustable about the second torsion bar, and an initial torque applied to the driving shaft portion positioned at the released position is adjusted by adjusting the fixing angle of the fixed member.